Intravenous leiomyoma with intracaval and intracardiac extension is a rare benign neoplasm affecting women. We report a case in which an intravenous leiomyoma originated from the right iliac vein and extended through the inferior vena cava into the right atrium. The correct diagnosis was made intraoperatively, after resection of the intracardiac extension of the tumor, which was 28 cm in length. At the 2nd stage of the operation, a right common iliac venotomy enabled the removal of all residual tumor from the inferior vena cava.